Groundwater Monitoring and Tritium at Indian Point

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April 8, 2016 Update on Groundwater Monitoring and Tritium at Indian Point


Our Expert Explains Remediation Program for Tritium at Indian Point


Ask an Expert – What is Tritium and Why Tritium Levels at Indian Point are Safe


Voices from Inside Indian Point – Our Experts Explain the Groundwater Monitoring Program

Information on Groundwater Monitoring Program and Elevated Tritium at Indian Point

Update On Groundwater Monitoring and Tritium at Indian Point

April 8, 2016


The causal analysis of the tritium event has identified that the direct cause is the operation of a temporarily installed reverse osmosis filtration unit that was in use at Unit 2 for approximately two weeks in January 2016. This finding is confirmed by several facts:

  • The spectroscopy and chemical signature of groundwater samples indicates the presence of reject water from this filtration unit.
  • The declining concentration of tritium in groundwater shows that that the release was a onetime event and has stopped.
  • The time frame for the presence of the tritium parallels the operational period of the filtration unit.
  • Location of affected wells indicates the release occurred at Unit 2.
  • Inspection, testing and chemical signature of other components has excluded them as credible sources.

The Root Cause Failure Modes Analysis (FMA) is nearly complete with one action remaining. This action, testing the fuel storage building truck bay floor, cannot be completed until after the refueling outage is complete.

In response to the direct and contributing causes identified in the analysis, the following actions are being taken:

  • Revise the reverse-osmosis filtration unit operation to prevent interaction with any groundwater paths.
  • Investigate and clean all Unit 1, 2 and 3 floor drains.
  • Place the aforementioned floor drains in a preventive maintenance program.
  • Perform an Extent of Condition review on systems that are comparable to the reverse- osmosis filtration unit operation to prevent a similar occurrence.
  • Any additional corrective actions required as a result of the truck bay floor.
  • Upgrade existing environmental awareness training to demonstrate how work practices can impact groundwater.
  • Evaluate and develop design details to harden the site against leaks.
  • Conduct a cross-disciplinary focused self-assessment of the site groundwater monitoring program.
  • Conduct a site-wide communication to inform all employees on the event and to discuss how work practices can adversely impact groundwater.

Samples taken from groundwater monitoring wells from around the site since Entergy first detected the issue have shown generally declining levels of tritium – one of the weakest radioisotopes – in groundwater, with some expected exceptions as the material migrates underground. This event was reported voluntarily to federal and state authorities in early February.

As previously stated, drinking water and Hudson River aquatic life were not affected. Even at their highest levels tritium never exceeded one-tenth of one percent of US Nuclear Regulatory Commission limits. Measurements of groundwater and river water verified there is no threat to human health or the environment.

In addition to the event analysis and ongoing monitoring, we are acting on advice from the NRC, by extracting water at a monitoring well to lower the localized concentration of tritium, strengthening the detection capability. We are also installing a groundwater extraction system that had originally been planned for late this year.

We are keeping local governments, members of Congress, regulatory agencies and other stakeholders informed through a regular series of conference calls with technical experts.

Indian Point takes accountability for running a safe and secure operation seriously and acknowledges that it fell short of the high standards the community has come to expect from it. Company leadership has assembled a dedicated team of external and internal experts to help understand what happened and prevent a recurrence.

Tritium

Tritium is a naturally occurring radioactive form of hydrogen that is produced in the atmosphere when cosmic rays collide with air molecules. As a result, tritium is found in very small or trace amounts in groundwater throughout the world. It is also a byproduct of the production of electricity by nuclear power plants. Tritium emits a weak form of radiation, a low-energy beta particle similar to an electron.

Tritium is a low hazard radionuclide because it emits weak radiation that does not penetrate the skin.People could be harmed by tritium only through internal exposure caused by drinking water with high levels of tritium over many years.

Other radionuclides are also present at the site and we expect to find those in the groundwater. For example, antimony has been identified in groundwater samples and in other water samples, although at much lower concentrations than tritium. Antimony is a byproduct of nuclear power plant operations and is present in tanks and pipes at Indian Point. Like tritium identified in groundwater at Indian Point, measured releases of antimony as a result of this issue are far below federal reporting requirements at less than one-tenth of one percent of established limits.

It is possible additional radionuclides could be observed in future monitoring well samples. Our conservative estimates have determined any potential releases of any radionuclide as a result of this issue would be far below federal reporting requirements.

Water Purge Process

Indian Point will reduce concentrations of tritium in the monitoring well that experienced the highest levels to provide increased sensitivity. This will enable the monitoring system to detect any potential lower level tritium issues if they were to occur in the near future. The concept of withdrawing water from this monitoring well was recommended by the US Nuclear Regulatory Commission and is being implemented in March 2016. The water purged from this well will be captured and processed in accordance with the plant’s normal wastewater filtration and discharge process.

Tritium at nuclear power plants

According to the NRC, more than 2/3 (46 out of 65 locations where nuclear power plants are sited) of US nuclear power plants have reported abnormal releases of water containing tritium (leaks or spills that involved tritium in excess of 20,000 picocuries per liter), resulting in groundwater contamination. Tritium rapidly disperses and dissipates in the environment, and as a result, tritium from leaks or spills is typically not detected outside the facility boundary.

Like normal hydrogen, tritium can bond with oxygen to form water. When this happens, the resulting water (called "tritiated water") is radioactive. Tritiated water (not to be confused with heavy water) is chemically identical to normal water and the tritium cannot be filtered out of the water.

Nuclear power plants routinely and safely release dilute concentrations of tritiated water. These authorized releases are closely monitored by the utility, reported to the NRC, and made available to the public.

Tritium and dosage to the public

Tritium is present naturally in the environment and the radiation produced by natural tritium is identical to the radiation produced by tritium from nuclear power plants.

The radiation dose from tritium can be directly compared to the radiation dose from any other type of radiation, including natural background radiation and those received during medical procedures.

The tritium dose from nuclear power plants is much lower than the exposures attributable to natural background radiation and medical administrations.

In all the cases of groundwater contamination evaluated to date, none has exceeded any of the NRC's dose limits or any of the licensee's Technical Specification Limits.

Humans receive approximately 50% of their annual radiation dose from natural background radiation, 48% from medical procedures (e.g., x-rays), and 2% from consumer products. Doses from tritium and nuclear power plant effluents are a negligible contribution to the background radiation to which people are normally exposed, and they account for less than 0.1% of the total background dose (NCRP, 2009).

Tritium at Indian Point

Tritium has never been detected in drinking water wells offsite near Indian Point and no wells on-site are for drinking water. No tritium other than natural background levels has been found offsite, nor would any be expected from this recent finding.

The main regulatory agencies for Indian Point operations and effluent releases are the Nuclear Regulatory Agency and the New York State Department of Environmental Conservation. The NRC and DEC oversee IPEC's response to any leakage issues. The NRC governs and enforces the laws and limitations with regard to radiological effluent releases while the DEC focuses on non-radiological releases.

Although the levels of tritium released to groundwater are well within NRC's permitted limits for monitored releases and do not pose a threat to public health and safety, Entergy made voluntary notifications to the NRC and other local and state stakeholders, and the NRC intends to have inspectors review this recent matter to determine the likely cause.

Indian Point is implementing a groundwater remediation program beginning in 2016, which will involve pumping tritiated water out of the ground, thereby further reducing the potential for adverse environmental consequences related to this event.

For more information please read the following:


Frequently Asked Questions

What is tritium?

Tritium is a naturally occurring radioactive form of hydrogen that is produced in the atmosphere when cosmic rays collide with air molecules. As a result, tritium is found in very small or trace amounts in groundwater throughout the world. It is also a byproduct of the production of electricity by nuclear power plants, and emits a weak form of radiation.

Why did tritium leak from Indian Point?

Tritium was identified in elevated concentrations in groundwater monitoring wells at Indian Point in early February 2016. While a review of the factors that led to tritium reaching the groundwater is under review, the most likely cause of elevated concentrations of tritium in groundwater is related to work done during routine processing of a volume of water in preparation for an upcoming maintenance and refueling outage at Indian Point Unit 2.

During the processing of this volume of water a waste stream is produced, which was then directed by design to a waste collection system. The most likely cause is this system failed and caused some of the waste stream water to enter the ground. There is a team dedicated solely to this investigation onsite to further review this matter.

Can it harm me?

Tritium is a low hazard radionuclide because it emits weak radiation that does not penetrate the skin. People could be harmed by tritium only through internal exposure caused by drinking water with high levels of tritium over many years.

There is no pathway for tritium in the ground at Indian Point to affect humans or aquatic life in the river, thus there is no consequence to anyone from the elevated tritium in groundwater at Indian Point.

Can tritium from Indian Point contaminate drinking water?

No. There is no pathway for tritium in the ground at Indian Point to affect drinking water anywhere. There are no wells on-site at Indian Point for drinking water, and no tritium other than natural background levels has been found offsite, nor would any be expected from this recent finding.

Did you report this recent measurement of elevated tritium in groundwater at Indian Point to the government?

Because the effect of these elevated values of tritium is less than one-tenth of one percent of federal reporting guidelines, there was no requirement to notify the government. However, Entergy made voluntary notifications to the U.S. Nuclear Regulatory Commission, the state of New York, and other key elected officials and stakeholders.

The NRC has independent inspectors who review operations at all U.S. nuclear power plants each day, including Indian Point.

Is the leak or spill ongoing?

No. The leak or spill of water to the ground was likely related to a specific work activity that is no longer occurring or needed.

What are the long term consequences of this event?

There is no consequence to public health or safety, nor is there any consequence to aquatic life in the river as a result of this issue.

While elevated tritium in the ground onsite is not in accordance with our standards, there is no health or safety consequence to the public.

What is the plan going forward?

As it so happens Entergy already has a remediation system planned to be installed later this year at a nearby location that will be effective for this situation. We are determining how to accelerate the implementation of this system so that it can be put into service sooner.

It is important to remember that even without a remediation system in place, there is no consequence to public health or safety as a result of this event.

Dr. Kimberlee Kearfott, Professor of Nuclear Engineering and Radiological Sciences at the University of Michigan, conducted an independent study on the elevated tritium levels found in the groundwater monitoring wells at Indian Point in 2016. More from Dr. Kearfott: I was engaged by Indian Point to perform an expert technical review of the events surrounding the inadvertent release of tritium to the ground water at Indian Point that occurred on January 16-17, 2016. Although my report, in its entirety, is not complete and ready for release, I am able to state with confidence that the release of tritium to the ground water that occurred in January is of such a small magnitude that no measurable or detectable environmental or public health consequences could have occurred or will occur in the future. Furthermore, I am able to confidently state that the methods and analyses used to determine the size of the release are consistent with good scientific and technical practices and the resulting calculations for environmental and public health impact are quite conservative (that tends to overestimate any impacts).



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